子类化Python类以继承超类的属性

Question

I'm trying to inherit attributes from a super class but they are not being initialized correctly:

class Thing(object):
    def __init__(self):
        self.attribute1 = "attribute1"

class OtherThing(Thing):
    def __init__(self):
        super(Thing, self).__init__()
        print self.attribute1

This throws an error since attribute1 is not an attribute of OtherThing, even though Thing.attribute1 exists. I thought this was the correct way to inherit and extend a super class. Am I doing something wrong? I don't want to create an instance of Thing and use its attributes, I need it to inherit this for simplicity.

Answer 1

You have to give, as argument , the class name (where it is being called) to super() :

super(OtherThing, self).__init__()

According to Python docs :

... super can be used to refer to parent classes without naming them explicitly , thus making the code more maintainable.

so you are not supposed to give the parent class . See this example from Python docs too:

class C(B):
    def method(self, arg):
        super(C, self).method(arg)

Answer 2

Python3 makes this easy:

#!/usr/local/cpython-3.3/bin/python

class Thing(object):
    def __init__(self):
        self.attribute1 = "attribute1"

class OtherThing(Thing):
    def __init__(self):
        #super(Thing, self).__init__()
        super().__init__()
        print(self.attribute1)

def main():
    otherthing = OtherThing()

main()